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McIntosh Solar Microscope & Stereopticon

From the Journal of the Royal Microscopical Society, 1889

Dr. L.D. McIntosh devised this apparatus for use with solar or artificial light for projecting or photographing microscopic objects with oblique illumination, or projecting opaque objects, and before describing it, he explains the construction of his solar microscope and stereopticon combination (fig 1). The optical parts can be used with either solar or artificial light, with only slight changes. To use sunlight, there is a plane mirror, 12x14 inches, which turns on a vertical horizontal axis by means of spur wheel gears connected with rods. The gears are supported by a bracket which is securely clamped to a perpendicular board. On the front of this board is an opening to receive the condensing lens, which is mounted in a brass tube with draw tube. The draw tube has a screw thread to receive either the microscopic attachment for prjecting microscopic objects, or a stereopticon lens for projecting photographic transparencies. By means of the thumbwheels, the mirror can be adjusted at any angle desired for illuminating a transparency or microscopic object.

To use the solar microscope or stereopticon, place it in a window exposed to direct sunlight and adjust the mirror so that the light enters the condensing lens parallel with its axis; adjust the microscope or stereopicon lens; place the object on the stage, or, if a transparency, in front of the condenser, and a well-defined image is seen on the screen To use the optical parts of the instrument just described with artificial light, viz. oxy-hydrogen or electric, remove the brass tube containing the condensing lens and draw tube from the mirror attachment and connect to the combination stereopicon, using either the stereopticon lens or microscope as desired. The light is centered and adjusted by means of thumb screws on the oxy-hydrogen jet. The adjustment is the same as with solar light. The only change (two condensing lenses are used with artificial light), one of these lenses is removed and only one used, and a small secondary condenser placed under the stage of the microscope. With this combination just described, we can only project, with transmitted light, transparent objects.

The attachment (fig 2), is for photographing and projecting objects with oblique illumination, or projecting opaque microscopic objects. It is constructed as follows: To the base of the combination stereopticon is clamped a triangular piece of brass U, by means of thumb screws, with a slot near its apex to hold a movable hollow pillar. This pillar is slotted on one side and has a screw and clamp to hold a perpendicular pinion, which, in turn, receives the stage and working part of the stand, which is securely clamped by means of a screw. Extending through from the lower end of the pillar is a screw for lowering or raising the stage of the microscope and body tube. The body tube of the microscope is in a horizontal position and the stage is vertical. These are directly in front of the condensing lens. By means of a pinion in the pillar, the microscope can be rotated horizontally to the right or left. The center of an object on the stage corresponds with the center of motion. By means of this rotation any angle, either of solar or artificial light, can be obtained for photographing and projecting, also projecting opaque microscopic objects or projecting with transmitted light.

To use the attachment with solar light, the plate can be removed from the stereopticon and attached by means of a bracket to the front of the mirror board of the solar instrument, adjusted the same as with artificial light. For photographing microscopic objects a camera box must be connected with the tube.

Fig 1 Fig 2 McIntosh

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